Factory Method Pattern

2023-10-11 in Design Patterns

Factory Method Pattern에 대해 설명하는 페이지입니다.

Environment

• Programming Language: Java

Index

• Index
• Introduction
• How to Use (Example)
• Comments

Introduction

• Purpose
  • Exposes a method for creating objects, allowing subclasses to control the actual creation process.
• Use When
  • A class will not know what classes it will be required to create.
  • Subclasses may specify what objects should be created.
  • Parent classes wish to defer creation to their subclasses.
• Characteristics
  • Uses inheritance to decide the object to be instantiated.
  • Defines an interface for creating an object, but lets subclasses decide which class to instantiate.
  • Lets a class defer instantiation to subclasses.

How to Use (Example)

• Product

  public abstract class MyProduct {
      String name;
  
      public String getName() {
          return name;
      }
  }
  

• Concrete Products

  public class ProductA extends MyProduct {
      public ProductA() {
          name = "ProductA";
      }
  }
  
  public class ProductB extends MyProduct {
      public ProductB() {
          name = "ProductB";
      }
  }
  
  public class ProductC extends MyProduct {
      public ProductC() {
          name = "ProductC";
      }
  }
  
  public class ProductD extends MyProduct {
      public ProductD() {
          name = "ProductD";
      }
  }
  

• Creator

  public abstract class MyCreator {
      public MyProduct orderProduct(String type) {
          Product product = createProduct(type);
          return product;
      }
  
      protected abstract MyProduct createProduct(String type);
  }
  

• Concrete Creators

  public class CreatorAB extends MyCreator {
      public MyProduct createProduct(String type) {
          Product product;
          if (type.equals("A")) {
              product = new ProductA();
          } else if (type.equals("B")) {
              product = new ProductB();
          }
          return product;
      }
  }
  
  public class CreatorCD extends MyCreator {
      public MyProduct createProduct(String type) {
          Product product;
          if (type.equals("C")) {
              product = new ProductC();
          } else if (type.equals("D")) {
              product = new ProductD();
          }
          return product;
      }
  }
  

Comments

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